Crystal Lattice Structures
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Introduction

Simple Cubic

Body Centered Cubic

Face Centered Cubic

Primitive FCC

Simple Hexagonal

Hexagonal Closest Packing

HCP Coordination

Cubic Closest Packing

CCP Coordination

Rhombohedral

2- & 3-Layer repeats

4-layer repeats

Tetrahedral Holes

Octahedral Holes

CsCl

NaCl

Halite

Fluorite

Zinc Blende

Exercises
Coordination in CCP
  Each host atom in a CCP lattice is surrounded by and touches 12 nearest neighbors, each at a distance of 2r: 
  • There are six atoms in the central A layer;
  • There are three atoms  in the B layer above the A layer; 
  • There are three atoms in the C layer below the A layer.
The six atoms in the B and C layers form a trigonal antiprism (also known as a distorted octahedron) around the central atom;  the length of this prism (the distance between the two equilateral triangular faces) is 2.CPIS.r, but the length of the long edges of the six isosceles triangular faces is slightly greater than that value.

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Steven F. Watkins, Department of Chemistry, Louisiana State University